OFFSET
1,1
COMMENTS
Numbers b such that A255920(b) = 3.
LINKS
Felix Fröhlich, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Wieferich Prime
PROG
(PARI) is(n) = my(i=0); forprime(p=1, n-1, if(Mod(n, p^2)^(p-1)==1, i++); if(i > 3, return(0))); i==3
(Sage) [b for b in range(3, 458) if len([p for p in range(2, b) if is_prime(p) and mod(b, p^2)^(p-1)==1])==3] # Danny Rorabaugh, Mar 31 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Felix Fröhlich, Mar 23 2015
STATUS
approved